NASA image shows U.S. heat wave that turned winter to summer

View full sizeNASA Earth ObservatoryThe extent of the March heat wave is captured in this NASA Earth Observatory image.

View full sizeNASAMore than 1,000 locations broke temperature records for warmth between March 13 and 19 across the U.S. and Canada.

When it comes to record-shattering March heat, a picture really is worth a thousand words. NASA’s Earth Observatory released an image of North America illustrating the extent of this heat wave, which has turned winter into summer for 1,054 locations that experienced record high temperatures between March 13 and 19 across the U.S. and Canada. Another 627 locales broke records for warmest daily lows, according to

The images at right show the intensity and scope of the huge, lingering ridge of high pressure over central North America. The map shows land surface temperature anomalies based on data from the Moderate Resolution Imaging Spectroradiometer (

) instrument on the Terra satellite. The image depicts temperatures compared to the average same eight-day period of March from 2000 to 2011. Areas with warmer than average temperatures are shown in red. Near-normal temperatures are white and areas that were cooler than the 2000-2011 base period are blue.

In West Michigan on Tuesday — the first official day of spring, and smack in the middle of the big red blotch on the map — the weather has seemed more like the lazy days of summer. High temperatures broke previous records for the

noted that weather records are not only being broken across the country, but "they're being broken in unusual ways."

"Chicago, for example, saw temperatures above 80 degrees every day between March 14 and 18, breaking records on all five days. For context, the National Weather Service noted that Chicago typically averages only one day in the eighties each in April. And only once in 140 years of weather observations has April produced as many 80 degree days as this March."

According to Jeff Masters at Weather Underground, the weather system responsible for the heat is a large upper-level ridge of high pressure "stuck" in place, a phenomenon known as a "blocking pattern." The jet stream is basically splitting the country in two, and the fact that it's lasting this long is an extreme rarity.

"If the current model forecasts prove correct, a high pressure ridge over the U.S. bringing heat this intense and long-lasting in March will be unprecedented in the historical record, going back to 1872," Masters writes.

that in northern Michigan, overnight lows have been running warmer than the typical daytime highs for this time of year, which are normally in the 30s to low 40 degrees range.

"In Marquette, Mich., the weather has been warm enough to melt 4 feet of snow in two weeks, with little to no snow cover on the ground now — a rare occurrence for mid-March. The Great Lakes have also lost nearly all of their ice cover at a time of year when they are typically just starting to see a decrease from the winter peak."

So, since we've established that this heat wave is unprecedented in the time since modern U.S. weather records began in the late 19th century, what's